In the recent Supreme Court case Herring v. United States, the majority determined that courts may not throw out evidence in cases where the police may have violated a suspect's Fourth Amendment rights due to "isolated negligence." The case represents further erosion of the exclusionary rule, a doctrine dating back to 1914 (with some weaker antecedents in English law) holding that evidence obtained through unconstitutional police procedures can't be used against a defendant at trial.
Conservatives have long despised the exclusionary rule, arguing that it protects the guilty (by disallowing evidence of their guilt at trial) and does little to protect the innocent (those who've done nothing wrong aren't going to be prosecuted). There's some merit to those arguments. It is an imperfect remedy to search and seizure violations.
The problem is that right now, it's really the only remedy. If police officers can make a case against someone using evidence they obtained illegally, what's to stop them from disregarding the Fourth Amendment entirely?
There are multiple problems with suing police. It's of course unlikely that anyone convicted with tainted evidence is going to sue. That leaves those wrongly searched in cases where police didn't find anything incriminating, a group of people likely to already feel intimidated, and who may not recover enough in damages to merit the time and effort of a lawsuit.
The more direct hurdle to the use of lawsuits to halt police misconduct is that as government employees, the police have qualified immunity from such suits. They're effectively shielded from liability—even if they've done something unlawful—unless you can show they've violated "clearly established law," as determined by a reasonable person. Government employees need only to have the basic understanding of civil rights that the average, reasonable person might have, not the sort of specialized knowledge private professionals generally have about their work. So a police officer who shoots someone without provocation would be liable, but a police officer who takes illegal shortcuts to get a warrant to search your home probably wouldn't.
You needn't have sympathy for the sketchy defendants in Fourth Amendment cases to be concerned about what's going on here. If you take away the exclusionary rule and you make it increasingly difficult to sue police officers for search and seizure violations, the Fourth Amendment carries all the literal weight of the parchment on which it's written. Without an enforcement mechanism, it's meaningless.
Some—most notably Supreme Court Justice Antonin Scalia—have argued that the Exclusionary Rule is no longer necessary, because there's a "new professionalism" that's been sweeping police departments over the last 20 or so years. Scalia first made that argument in the 2006 case Hudson v. Michigan. He may be right that police today are more cognizant of civil liberties than they were in the 1950s or 1960s. But "better" doesn't necessarily equate to "acceptable." The "Blue Wall of Silence"—the code by which police officers refuse to testify against one another—hasn't exactly broken down. In just the last year, police departments in Atlanta, Oakland, and Chesapeake, Va., have come under fire for taking shortcuts on search warrants, including outright lying.
Dr. Sam Walker, one criminologist Scalia referenced in his Hudson opinion, actually took to the pages of The Los Angeles Times to denounce how Scalia had interpreted his work. Yes, Walker wrote, police departments have gotten more professional over the years, but it's because the Supreme Court strengthened constitutional protections for criminal suspects in the 1960s and 70s. To use his conclusions to then argue that those protections are no longer necessary, as Scalia did, was disingenuous. Justice Ruth Bader Ginsberg made a similar argument in her dissent in the Herring case, writing that, "It has been asserted that police departments have become sufficiently 'professional' that they do not need external deterrence to avoid Fourth Amendment violations. But professionalism is a sign of the exclusionary rule's efficacy—not of its superfluity."
In response to the Court's ruling in Herring, University of Tennessee law professor Glenn Reynolds proposed a grand bargain to the law-and-order crowd: He'd give up the exclusionary rule, if they'd work with him to get rid of qualified immunity.
It's not a bad deal. In fact, it would be a good idea to get rid of qualified immunity for all government employees. They idea that getting a government paycheck somehow inoculates you from liability should you harm someone while on the job is antithetical to the principle of equality under the law. If anything, the government should be held to a higher standard.
I'd add, though, that opening police officers up to lawsuits probably isn't enough. There's an interesting dichotomy on the right when it comes to the police. The same philosophy that distrusts the government when it manifests itself as bureaucrats and regulators (a sentiment I share) seems to put an unhealthy amount of trust in the government employees we call police officers. The sentiment among many on the right is that the police need less supervision, less watch-dogging, and less second-guessing than other government emlpoyees. This is particularly odd given that, compared to your average bureaucrat, police officers are entrusted with an extraordinary amount of power, at least when it comes to the power they wield over the people with whom they come into contact. They are as susceptible to the same trappings of power as any scorned EPA regulator or grudge-bearing city council member, only they're also entrusted with the power to detain, use force, and kill.
My point is not that police officers on an individual level are terrible people, or more prone to misbehavior than your typical government employee or your typical citizen. The problem comes when the weaknesses that are in all of us are coupled with a license to use force, authority, and the sense that one is above the law. Philip Zimbardo's famous Stanford prison experiments showed that it doesn't matter who you put in that position, the results can be disastrous without the proper controls. We can't do anything about the first element, and the second and third are by definition part of policing. It's that last one that we can change.
To make matters worse, for the last 30 years politicians have trumpeted a "get tough on crime" message that has resulted in measuring police departments and prosecutors primarily by how many people they're able to arrest and toss in jail. There's a huge push for arrests, and a de-emphasis on civil liberties. It isn't difficult to see the sorts of incentives that sets up.
If we're going to get rid of the exclusionary rule, it needs to be replaced not only with alternative punitive measures, but also with a wholesale change in mindset that emphasizes the "keeping the peace" approach to policing, as opposed to merely racking up arrest statistics.
I don't see either happening any time soon.